If the problem is intermittent (sic?), then it may be a loose jumper on one of your drives. An inch of Electrical tape, placed correctly, goes a long way.

If I recall correctly, he said he already put electrical tape over the jumper. But if the jumper is loose (i.e., the pins don't make solid contact against the jumper), then electricaly tape will only prevent it from falling off, it won't take care of the intermittency. If this is the case, bending the pins slightly might help.

Although I would say it's more likely to be a "dodgy cable" at this point. Ernest, have you contacted Support yet about replacing the cable?